Various proposals have been made heretofore for auxiliary brake controls on automobiles to enable a driving instructor sitting in the passanger's side of the front seat to apply the brakes of an automobile operated by a student driver. Such prior proposals have not been entirely satisfactory because of various factors, including the undue complexity of the linkage between the auxiliary brake pedal and the driver's brake pedal, the unsatisfactory manner in which the auxiliary brake pedal and this linkage are supported physically, the lack of ready adjustability to suit the preferences of individual driving instructors, and the obstruction of the feet and legs of the driving instructor. Examples of such proposals for this general purpose are disclosed in the following U.S. patents: Nafe et al U.S. Pat. No. 2,647,414; Berman U.S. Pat. No. 2,677,976; Holum U.S. Pat. No. 2,720,121; Garver U.S. Pat. No. 2,814,212; Rose U.S. Pat. No. 3,174,359; and Allgaier U.S. Pat. No. 3,435,703.